This invention relates to a casing for a semiconductor memory chip.
It is a recent trend that a great number of memory elements are highly integrated in a single semiconductor memory chip. In order to package such a semiconductor memory chip into a packaged memory device, use is made of a casing comprising a base member and a cap member. With the memory chip mounted on the base member, the cap and the base members are hermetically sealed together by a sealing layer of glass frit to form a hollow space in which the memory chip is placed. It is recently pointed out that soft errors take place in the memory elements of the packaged memory device. This is because alpha particles are emitted from the casing onto the memory elements.
As will later be described with reference to one of several figures of the accompanying drawing, the sealing layer of glass frit occasionally emits objectionable alpha particles onto the memory chip. In addition, the soft errors are often dependent on the alpha particles emitted from the cap member.